Rudder Servo

[Chris_nunes]

Want your glider to navigate to victory? hopefully this will help. Attached are the early instructions for how to use a rudder servo on your glider.
PLEASE ASK QUESTIONS!!
If this document is not perfectly clear to you, that is fine, post a question and let us all grow our knowledge together.
Remember that these are advanced modules and not the well tested solutions in the rest of the kit so there will probably be bugs and surprises. PLEASE SHARE THEM!!

[Chris_nunes]

if you attach a tail servo, you probably want to connect it to your rudder.
This part can help attach your existing rudder to the servo horn.

[Will Lamborn]

This was so helpful! thank you so much.

Have a probably dumb question but here I go. I have tested the rudder servo with a servo sweep and it works, then I tested the basic seaglide code and it works. My problem is when I try to place the rudder servo code into the seaglide code, the rudder servo won't run until the plunger waits to change directions. Even then, the rudder servo kind of just fidgets in place instead of actually turning. I don't know how to fix this.

please help

[Chris_nunes]

I am glad it was helpful, and its not a dumb question!
When placing the rudder.write(val) command into the seaGlide code, be careful to make sure it is called during the rise, dive, and pause functions otherwise it will be ignored while the void loop() is executing the other functions. I suggest making your own function like "void steer()" and call it in all of the functions where the Arduino spends most of its time (mostly while loops).
The servo does tend to twitch right now due to some timer conflicts with the IRlibrary, but it should still respond. A good way to debug this is to Serial.println(theValue) that you are writing to the servo and make sure the code is doing what you expect. Some times something as simple as 1/2 can equal zero in micro controller language due to the overly specific nature of fixed point math.(eg. 1/2=0 and 1.0/2.0=0.5)

Sorry for the slow response, I hope it helps!

[mpustie]

How does the rudder know in what angle to move without a compass? Let's say that the glider is to traverse a pool due north in the quickest time. Using a magnetic compass which would sense how much the glider was deviating from the north direction in degrees and then compensate by moving the rudder appropriately makes sense to me. Isn't some sort of electronic sensor required here? What am I missing? Thanks in advance for any insight!

[JCampana]

You are absolutely correct. Adding just a rudder allows you to give your glider the ability to steer, but without input you are still steering blind. A compass/magnetometer is one way to feed direction to your glider to get it to go in a straight line. For example, we have used Adafruit BNO055 9DOF IMU in one of our gliders.
Another way to feed direction information to you glider could be to use light sensors and make your glider follow a bright light or a certain color of light.
You could also use a sound sensor to listen for simple commands, directing your glider to turn either right, left, or straight. Some students we have worked with have used the SparkFun Sound Detector to do something similar.

[mpustie]

In reviewing Rudder Servo V1.0pdf, the same 9V 500 mAh battery is powering 2 Servo Motors ( Buoyancy Engine and Rudder.) 1) What if one wants to power additional sensors? Is it better to add an additional battery or simply purchase a 9V rechargeable battery with a higher mAH rating? 2) In the document, it is suggested to solder a wire around the RAW pin. Unfortunately, that pin is not free when the SeaGlide Board is plugged into the Arduino Pro Mini. Am I correct in saying that the RAW pin is not available anywhere else on the SeaGlide board?

[David Young]

In reviewing Rudder Servo V1.0pdf, the same 9V 500 mAh battery is powering 2 Servo Motors ( Buoyancy Engine and Rudder.) 1) What if one wants to power additional sensors? Is it better to add an additional battery or simply purchase a 9V rechargeable battery with a higher mAH rating? 2) In the document, it is suggested to solder a wire around the RAW pin. Unfortunately, that pin is not free when the SeaGlide Board is plugged into the Arduino Pro Mini. Am I correct in saying that the RAW pin is not available anywhere else on the SeaGlide board?

1) Standard 9V Li-ion batteries are rated between 0.8 and 1.2 Amps capacity. The standard SeaGlide (servo, Arduino, circuit board with LED) draws under 0.18 Amps. There is enough capacity for an additional servo or sensors, but the battery will drain faster. You should determine the power requirements of the additional components to assure you do not overload the battery. Using a higher mAh will increase the run time.
2) You can solder a wire to the backside of the power pin (Red) of the servo pins on the circuit board.

[mpustie]

To accomplish (2) on an already built board, I can desolder the 3 wired angled Servo connector, insert a new connector so I have enough surface for a wire connection, solder the Power wire to the underside of Servo(Red), and then solder the GND and Signal of the servo connector.

[David Young]

To accomplish (2) on an already built board, I can desolder the 3 wired angled Servo connector, insert a new connector so I have enough surface for a wire connection, solder the Power wire to the underside of Servo(Red), and then solder the GND and Signal of the servo connector.

To add another servo you will need to connect to Servo(Red) [RAW], GND, and a pin D13 from the PCB shown in the previous message.

I assume you are referring to the attached Rudder Servo_V1.0.pdf file? 3. Rudder Servo_V1.0.pdf

I found this after starting the conversation. The document also suggests that you can break out the power from the power harness.

[David Young]

JCampana Any other advice or corrections to the info I provided?

[mpustie]

My goal is to access Raw Power from the SeaGlide Board. Am I correct in saying that if I desolder the 3 wired angled Servo connector to the Buoyancy Engine Servo, insert a new connector so I have enough surface for soldering a wire connection to the Power wire to the underside of Servo(Red), I have access to Raw Power and can use it to power another servo? If this is still unclear, how can I connect to one of you offline? Thanks!

[David Young]

My goal is to access Raw Power from the SeaGlide Board. Am I correct in saying that if I desolder the 3 wired angled Servo connector to the Buoyancy Engine Servo, insert a new connector so I have enough surface for soldering a wire connection to the Power wire to the underside of Servo(Red), I have access to Raw Power and can use it to power another servo? If this is still unclear, how can I connect to one of you offline? Thanks!

Yes that would work, but I am not sure why it is necessary. The attached is an example of connecting a wire to the RAW pin (same as connecting to the servo red pin.

I sent my contact info via direct message.